Enabling Frame Body Capture Effect Month Year Doc Title Nov 17 Enabling Frame Body Capture Effect Date: 2017-11-06 Authors: Name Affiliation Address Phone Email Evgeny Khorov IITP RAS; NRU HSE khorov@frtk.ru Alexey Kureev IITP RAS   Ilya Levitsky IITP John Doe, Some Company

Nov 17 Problem In dense deployment, it may happen that a stronger frame from own BSS arrives when a STA is already synched to a weaker frame (e.g. from an alien BSS) Power time IITP

Receive State Machine (DSSS PHY) Nov 17 Receive State Machine (DSSS PHY) In the event that a change in PHYCS or PHYED would cause the status of CCA to return to the IDLE state before the complete reception of the MPDU, as indicated by the PHY LENGTH field, the error condition shall be reported to the MAC using a PHY-RXEND.indication(CarrierLost) primitive. The CCA of the DSSS PHY shall indicate a busy medium for the intended duration of the transmitted packet. IITP

Receive State Machine (OFDM) Nov 17 Receive State Machine (OFDM) IITP

Receive State Machine (11ax) Nov 17 Receive State Machine (11ax) The same happens here IITP

Consequences Power time Nov 17 In this case, both frames will be lost: The green one will be lost because of huge interference The red lime will be lost because the receiving STA was synched to the green frame However, at least red frames could be received IITP

Nov 17 Testbed We evaluated behavior of off-the-shelf devices in this scenario with the following testbed IITP

Frame Body Capture Effect IS NOT Present Nov 17 Frame Body Capture Effect IS NOT Present Frame receive ratio Both frames are lost IITP

Frame Body Capture Effect Is Present Nov 17 Frame Body Capture Effect Is Present Stronger frame is correctly received Frame receive ratio This is not aligned to the standard IITP

Real Devices Analyses Some devices support the feature Nov 17 Vendors and Device names are hidden Some devices support the feature IITP

Nov 17 Conclusion Allowing switching to a stronger frame is fruitful since give an opportunity to a STA to receive at least one frame in case of overlapped frames. This feature is currently implemented in some devices. This feature is not allowed by the standard. We need to allow this feature. In case of a stronger frame arrive, a STA may switch to this frame, operating as if the weaker frame were not received. IITP

Month Year Doc Title Nov 17 Straw Poll Do you agree that 802.11 should allow switching to a stronger frame during frame body of a weaker one Y N A IITP John Doe, Some Company

Nov 17 Motion - Do you agree to add the following para to the end of Sections 15.3.7, 16.2.6, 17.3.12, 19.3.21, 20.9, 21.3.20, 23.3.19 (all entitled ‘PHY receive procedure’)? It may happen that several frames overlap and a stronger frame starts later than the weaker one. To allow reception of at least the stronger frame, at any state of the PHY receive state machine, the STA can perform detection of a new frame start and switch to a new frame with higher power. Y N A IITP